pdp

What is the relationship between the voltage waveform presented and the load conditions? Actually generators that produce quite a bad sine wave can easily be found. Especially this concerns those cheap two stroke gasoline models made in China(improper rotor's material, poor isolation of windings etc.) All AC generators normally have some built-in voltage regulation system using their alternator's drive winding. This system may somehow conflict with UPS under certain load conditions.

That MC33172 is unlikely to be a full substitute for the widespread and extremely cheap LM358. The latter can suffice in many cases. For instance, LM358 is being used even by Intel in some computer motherboards. Perhaps it's still early to write this device off.

What trouble?

In the book of "The Art of Electronics", Chapter 7, on page 422 one can see the following schematic diagram and read this commentary: "Even though one side of R5 is connected to ground, it would be unwise to use a single-ended amplifier, since connection resistances of a milliohm would contribute 10% error! A differential amplifier is obviously required, but it need not have particularly good CMRR, since only very small common-mode signals are expected." So my question is: Which connections' resistances(segments of wiring) are exactly meant by authors? Thanks in advance to all who could be of any help to understand this.

In my opinion, it could make some sense if only the goal was to build a special featured device. Othewise it would just have to compete with great amount of those inexpensive factory-made voice recording gadgets that are easily available now.

We have got the only one design presented here so far. However, since we can see now strict figures perhaps it is also worth showing where the above mentioned -200mV may come from in the current design.

This sounds incomprehensibly. Owing to 555's single supply there is no way its output could go negative.